More than a billion people around the world will participate in Earth Day 2012 on Sunday.
One of this year's campaigns is called "A Billion Acts of Green." It's aimed at elevating the importance of environmental issues around the globe.
Earth Day has a lot of people wondering what they can do for the environment. Installing solar panels is a simple green solution, but they're not cheap.
But solar panels are now becoming more affordable because some companies are leasing them to homeowners and businesses.
"Leasing opens up a whole new class of consumers that just weren't available to solar," explained Vadim Polikov of Astrum Solar. "They may want to go solar; they may want to go green; they may want to be more independent from their utility company; but they didn't want to spend the money."
With a lease, the maintenance on the panels is part of the deal for the next 20 years; the homeowner doesn't have to worry about it.
And if you produce more solar energy than you use, the system sends a little bit of that back out into the grid and your electric meter will actually spin backwards. You get a credit for that power from your electric company.